Elsevier

Ophthalmology

Volume 107, Issue 6, June 2000, Pages 1144-1152
Ophthalmology

Ocular surface changes after excimer laser phototherapeutic keratectomy1

The preliminary work was presented at the 22nd Japan Congress of Cornea, February 1999, Ube, Yamaguchi, Japan. The finalized study was presented at the 99th Japanese Cataract and Refractive Surgery Congress, Kyoto, Japan, July 1999. This study has also been presented at the 5th International Nidek Excimer Laser User’s Meeting, Miyazaki, Japan, December 1999.
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Abstract

Purpose

To study the ocular surface disorder in patients with Avellino, granular, and lattice dystrophy, band keratopathy, and corneal leukoma before and after excimer laser phototherapeutic keratectomy.

Design

A prospective case-controlled study.

Participants

A total of 45 eyes of 33 patients with superficial corneal opacities seen at Kobe Kaisei Hospital, Department of Ophthalmology, and 40 eyes of 20 normal control subjects were studied.

Intervention

The subjects underwent routine ophthalmic examinations, corneal sensitivity measurements, tear film break up time (BUT), Schirmer test, tear film lipid layer interferometry, and conjunctival impression cytology.

Main outcome measures

The patients and the control subjects were compared for prephototherapeutic keratectomy (PTK) tear function parameters, tear film lipid layer interferometry grade, goblet cell density, and conjunctival squamous metaplasia grade. Alterations of these parameters within 3 months after PTK were also looked for.

Results

The average pre-PTK corneal sensitivity and tear film break up time were lower in patients compared with control subjects before PTK. Tear film lipid layer interferometry grade and conjunctival squamous metaplasia grades were higher in the patients than the controls before PTK. All these parameters improved gradually and significantly after PTK. Goblet cell density was significantly lower in the patients compared with controls before PTK. Schirmer test results and goblet cell density did not show any significant alterations after PTK.

Conclusions

Concurrent improvements in corneal sensitivity, tear film break up time, lipid layer interference grades, and conjunctival squamous metaplasia grades all point to the favorable effects of PTK on the ocular surface by improving the stability of the tear film and ocular surface health through attainment of a regular corneal surface and probably inducing qualitatively/quantitatively better mucin production by a healthier epithelium after PTK.

Section snippets

Subjects and examinations

Forty-five eyes of 33 patients with superficial corneal opacities (17 men, 16 women) between 34 and 84 years of age (mean, 66.7 ± 11.9 years) underwent excimer laser PTK at Kobe Kaisei Hospital Eye Clinic from September 1998 through April 1999. The etiologic distribution of superficial corneal opacities is shown in Table 1. All patients underwent routine ophthalmic examinations, including Landolt visual acuity and funduscopy, as well as ocular surface examinations consisting of Cochet-Bonnet

Clinical features

Superficial corneal opacities could be successfully removed from the corneal visual axis in all patients. The anterior segment photographs before and 3 months after PTK in a patient with band keratopathy are shown in Figure 1A, B. Thirty-one eyes (68.9%) had more than 2 lines of Landolt corrected and 6 eyes (13.3%) had 1 line of Landolt corrected visual acuity improvement after PTK in this series. Eight eyes (17.8%) showed no change of visual acuity after PTK. Four of these eyes had dense

Discussion

Excimer lasers have been and are being extensively used in the treatment of superficial corneal pathologic conditions after initial experimental and clinical reports of successful excimer laser therapeutic lamellar keratectomy applications. Many studies undertaken to assess the corneal tissue responses after excimer laser ablation increased our knowledge about the nature and quality of corneal wound healing. However, a better understanding of the causes and the course of the ocular surface and

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    The authors have no proprietary interest in any of the products mentioned in this paper.

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